This invention relates to devices for plugging holes, and, more particularly, to devices for plugging holes in ferromagnetic tanks.
Ferromagnetic tank structures are used throughout the world to store liquids, many of them hazardous to the environment. A particularly complex tank structure is formed by the hull of an ocean-going tanker, where such tankers can be super tankers that carry millions of gallons of hydrocarbon products, e.g., crude oil, gasoline, and chemicals. Each year there are numerous leaks from tankers, barges, and the like, with resulting damage to sensitive ecological systems and pollution of waterways. Statistics show that some 16,000 incidents occur each year with a release of 41,000,000 gallons released to the environment.
Leaks may occur from a number of sources, such as leaking fittings, small punctures, large tears in the side of the structure, and, increasingly, from fixed or drifting mines. By way of example, U.S. Pat. No. 5,355,824, to Meyer et al., incorporated by reference, teaches a framed bladder structure that can cover a large area and be attached to a ferromagnetic tank, such as the hull of a ship, by permanent magnets that be selectively placed in magnetic proximity to the tank surface for holding the framed bladder in place and forming a seal around the leak. In many instances, however, the leak may be from a fitting or fluid outlet formed in the structure or from a relatively small puncture of the tank. Then, a large area seal is not required, and it would be desirable to have available a simple device for sealing within a fitting outlet or a puncture.
It will be appreciated that the hydrostatic pressure of the liquid within a tank structure or exiting from a fitting outlet may be greater than the surrounding hydrostatic pressure. Under this condition it is difficult or impossible to manually approach and insert a sealing device within the breach or opening. Even a small device cannot be readily held in position to form a seal.
Accordingly, it is an object of the present invention to provide an insert for sealing within conventional fitting outlets and puncture-type penetrations in ferromagnetic tank structures, and particularly ship hulls.
Another object of the present invention is to provide a structure to assist in placing a sealing insert within a fitting outlet or puncture-type penetration against a hydrostatic pressure head.
One other object of the present invention is to anchor an insert placement structure to the tank surface while placing the sealing insert.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.